Coaster-brake for bicycles.



No. 69|,69Lv Patented lan. 2 I, |902.-

' A. F. wYMAN. y

CUASTER BRAKE FOR BICYCLES. (Application med may 1s. 1901. .(No Model.)

l C. im Mm 5o volve the hn'b in a forward direction,

wheel of a bicycle provided with my improvec is the shell of the hub, having its'ends UNITED l ST1-friesy .PATENT OFFICE.

COASTER- BRAKE FORl BICYCLES.'

sPEioIFIoATION Application and nay 13,1901.

To all whom it may concern: i

Be it known that I, ADOLPHUS F. WYMAN, a citizen ofthe United States of America, and a resident of New Bedford,in the county of Bristol and State of Massachusetts, have invented certain new and useful Improvements in Coaster-Brakes for-Bicycles, of which the following is a specification.

The accompanying drawings illustrate my invention, 1in which- Figure l is a rear view, in longitudinal vertical section, of the hub of the propellingments. Fig. 2 is a side view of one of the operating parts. y

Similar lettersrei'er to like parts in both views.

The letter a represents the stationary shaft of the bicycle, which is supported in the frame of Ithe' bicycleand is provided with the cones b b, integral therewith.

e is the sprocket, having the cylinder d in; tegral therewith, in the bottom of which cylinder is formed the ball-cup o, the ball-cup f being screwed in the end of the cylinder after theshaft a is adjusted therein.

o is a shoulder formed on the inner side of the sprocket c, to which is secured one end of the left-handspiral spring s.

t is a clutch which is rigidly secured to theshaft a, the construction "of which is shown in Fig. 2, which shows that when the rim k moves in a forward direction its motion is free; but when it moves in the opposite/direction in a slight degree the balls o roll up the inclines n and prevent its-furthermotiou in that direction. To the rim 7c of the clutch is secured the opposite end of the spring s. The clutch has its 'free motion when the wheel is being pedaled in a forward direction.

provided with the ball-cups'a; and g, the balls therein hearing-on the cones y and h. The coil of the spring s is'of slightly-larger diameter than the inside ef the shell of the hub e, so that it shall bey normally in frictional contact therewith.

The operation of -thedevice is as follows: When force is appliedto'the sprocket to re- .if the sprocket is the forming part of Letters Patent No. 691,691, dated January 21, 1902.

Serial No. 60,099. (No model.) f

spring s, which normally bears against the inside surface of the shell c, is brought in still greater frictional contact therewith and by its friction thereon causes the hub to turn with the sprocket. In descending an incline, held in a state of rest, the friction of the spring s' on shell c will sufficiently retard the motion of sprocket is revolved slightly in a backward di;

the inside of the y the wheel, and if the friction is too great the i rection by back-pedal`ing,which action, as the clutch i cannot revolve backward, servesto wind the spring s to asmaller spiral, thus removing to a greater or less extent its friction on the shell'c. In coasting, where it is desired to have the hub turn lfreely without any retarding force, the sprocket is revolved in a backward direction by back-pedaling until the spring s is wound to so small a spiral that it ceases to touch the inside of the shell c.

Having thus described my invention, what I claim, and desire to secure by Letters Patent, is

-A coaster-brake for a bicycle, comprising a stationary shaft,.having ball-cones integral therewith; acylinder or shell, surrounding said cones and adapted to revolve thereon by ball-bearings; a sprocket, integral with or secured to said cylinder; a shell or hub, surrounding said'cylinder, adapted to revolve on ball-bearings between cones, one of which is integral with the sprocket, and the other secured to the -stationary shaft; a spiral spring, surrounding said cylinder, having one end secured to the sprocket, a clutch, whose free movement is in a forward direction, secured to said shaft, and the opposite end of `said. spring, secured ltosaid clutch, said spring being normally in frictional contact with the interior of said hub, and adapted to be wound to a smaller spiral, by the'action of back-pedaling, v'substantially as shown, and described.

Signed by me at New setts, this 18thl day of April, 1901;

I ADOLPHUS F. WYMAN.

Witnesses:

EDWARD P. HAsKnLL,`Y

HENRY W. MASON. i

Bedford, Massachu; y l 

